This case concerns the question of who should be held vicariously liable for damages arising out of employees injured at work – the employer, third parties, or both? The appellant worked as a social worker for Durham County Council, which worked closely with two NHS trusts to provide integrated social care and mental health services.

One of the appellant's cases concerned a young girl whose father suffered from mental health problems and was a voluntary patient of both NHS trusts. He was known to have a history of violent behaviour. He told medical professionals that he wished to harm the social worker involved 79 in his daughter's case and later told medical staff he would "kill her on the spot" if he saw her. That threat was not passed to the appellant or to Durham County Council. The father left hospital and attacked the appellant with a knife, causing grave injuries. In the first instance, her claim against the NHS trusts was struck out on the basis that they did not owe her a duty of care in respect of the action of a third party.

The Court of Appeal allowed her appeal. Firstly, the court followed the test set out in Caparo Industries Plc v Dickman [1990] 2 AC 605 for the imposition of a duty of care toward a claimant for the actions of a third party. The test was that of foreseeability, proximity and fairness, justice and reasonableness. Therefore, it was not a pre-requisite for a claimant to show that the defendant had assumed any responsibility for some aspect of his or her safety. However, it was possible to infer an assumption of responsibility from the protocol or working arrangements between the respondents. Factors relating to foreseeability of harm and proximity of the relationship often also impinged on the question of fairness, justice and reasonableness. There might be some classes of claimant who stood in such a special relationship with the defendant public authority that it would be fair, just and reasonable to impose a duty of care. The appellant, given her special position, was within such a class. Taking the particular relationship between the parties into account, it would be open to a trial judge to conclude that it was fair, just and reasonable to impose a duty of care on the NHS Trusts. It was also arguable that the respondents might have breached the appellant's rights under Article 2 of the European Convention on Human Rights.

Read the full judgement here.